With the spring rains, fairy rings are making their annual return to our lawns.
Fairy ring mushrooms are the fruiting body created by any one of dozens of fungi that live on rotting woody material in the soil. They are one of the oldest life forms and their simple biology has enabled them to survive millions of years of change. As a result, getting them out of your lawn isn’t going to be easy. Sorry, folks, there is no quick fix here.
The woody material could be leftover construction debris or stumps and tree branches buried during a land-clearing project. Under the right conditions, the fungi spores develop into a fine white thread mass underground that slowly breaks down the woody debris into organic material and nutrients the soil and grass take up, creating the dark green ring in the lawn.
As the fungi advance, the green zone moves out and leaves behind an ever-enlarging patch of weakened or dead grass and a very dense filament mat. Poorly maintained, drought stressed lawns on light sandy soils are often the most affected and lawns with a heavy thatch buildup are particularly susceptible to the fungus.
There is no easy cure for fairy rings. Don’t be tempted to try lime, salt, fungicides or other supposed quick-cure remedies. Using them can actually cause more damage than the rings ever will.
There is only one way to eliminate it. You have to get water through the filament mat. This method is based on research done by scientists at Washington State University and will take about a month of time and close attention to procedures. No shortcuts.
1. Rake the mushrooms up or mow them off with the lawn mower.
2. Aerate the soil at least three inches deep with a spading fork or crowbar to open passages to the roots. Punch as many holes as you can, moving the fork or bar back and forth as you do to break up the soil profile even more. You can core aerate, but the coring tubes may not be long enough to give complete penetration.
3. Apply a wetting agent such as liquid dish soap or a commercial surfactant to help the water penetrate the soil. Use 1 teaspoon of soap per gallon of water and pour several gallons on the ring. The soap will not hurt the grass or kill the fungus; the soap breaks down the surface tension of the water, allowing it to flow more easily.
4. Drench the area thoroughly with plain water to the point of having standing water. Do not use a sprinkler – it will not get enough water on the lawn. Use a hose for large areas and buckets for small ones.
5. Repeat steps two, three and four every three days for four weeks. The fairy rings will begin to disappear after about two weeks, but do not give up. This process, though tedious, does work.
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